Abstract P3-13-10: Factors impacting surgical option in patients who achieved complete response in the breast after neoadjuvant systemic therapy

Abstract

Abstract Background: Neoadjuvant systemic therapy (NST) is the standard treatment for locally advanced breast cancer. Early studies have demonstrated that the rate of breast conservation was significantly increased and NST is now widely applied to operable breast cancer to increase breast conservation rate and to achieve better cosmetic outcome after breast conservative surgery (BCS). For patients who achieved pathologic complete response (pCR), they were perfect candidate for BCS. However, data from prospectively randomized trials have shown that, with the significantly increase of pCR by adding new drugs in the neoadjuvant regimen, BCS rate does not significantly increased. The purpose of current study is to identify factors that have influence on surgical option in patients that have achieved complete response in the breast after NST. Methods: From January 2009 to July 2016, 1150 patients with breast cancer received NST in our institute. There were 103 patients achieved complete response (CR) in the breast and were included in current analysis. Medical records were reviewed regarding to individual surgeon, pre-NST clinicopathologic characteristics, and post-NST image findings. Risk factors for mastectomy were assessed by univariate and multivariate analyses. Results: Of the 103 patients who achieved CR in the breast, 40 of them (38.8%) received mastectomy. In univariate analysis, physician factor, larger initial tumor size, advanced clinical stages, as well as post-NST image findings including skin change, residual tumor ≥3 cm, short nipple-tumor distance, and residual axillary lymph node(LN) on ultrasound and segmental/diffuse distribution of malignant calcification on mammography were associated with more mastectomy. In multivariate analysis, physician factor (OR=5.192, CI [1.562 – 17.257], p=0.021), residual axillary LN on echography (OR=4.000, CI [1.552 – 10.319], p=0.004), and segmental/diffuse distribution of malignant calcification on mammography (OR=7.500, CI [1.819 – 30.916], p=0.018) were independently related to mastectomy in patients who achieved CR in the breast after NST. Conclusion: Physician factor, residual axillary LN and segmental/diffuse malignant calcifications were risk factors for mastectomy in patients who achieved CR in the breast after NST. In addition to embrace current treatment guidelines of surgical management after NST, our data provide valuable additional information to avoid unnecessary mastectomy. Citation Format: Kou H-W, Shen S-C, Chen S-C. Factors impacting surgical option in patients who achieved complete response in the breast after neoadjuvant systemic therapy [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-13-10.